package com.jiao.springcloud.lb;

import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

@Component
public class MyLb implements LoadBalancer{

    private AtomicInteger atomicInteger = new AtomicInteger(0); //初始为0

    private final int getAndIncrement(){
        int current;
        int next;
        do {
            current = this.atomicInteger.get(); //0
            next = current >= 2147483647 ? 0 : current + 1;
        }while (!this.atomicInteger.compareAndSet(current,next));   //自旋：当前值=期望值：修改值
        System.out.println("*****第几次访问next:"+next);
        return next;
    }

    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }
}
